Aminoanthraquinones are generally useful as dyes and coloring agents for the coloring of materials such as cellulose derivatives and for coloring artificial compositions such as oils, waxes, detergents, and granulated bleaches. For example, U.S. Pat. Nos. 2,050,704 (issued Aug. 11, 1936), 2,121,928 (issued June 28, 1938), 2,191,029 (issued Feb. 20, 1940), 2,191,030 (issued Feb. 20, 1940), and 2,188,369 (issued Jan. 30, 1940) all disclose substituted anthraquinone compounds and their uses as dyes. More recently, U.K. patent application Nos. 2,014,178 (published Aug. 22, 1979) and 2,019,870 (published Nov. 7, 1979) have disclosed a class of halogenoanthraquinones useful for dying and printing textile materials.
U.S. Pat. No. 2,121,928, issued to Peter, discloses a method of synthesizing substituted aminoanthraquinone compounds by condensing certain aromatic amines with halogen, sulpho-, or alkyl-substituted anthraquinone compounds at elevated temperatures in the presence of a catalyst.
U.S. Pat. No. 2,183,652, issued to Lord, discloses a method of synthesizing substituted aminoanthraquinone compounds by reacting quinizarin (1,4-dihydroxyanthraquinone), 1,4,5-trihydroxyanthraquinone or 1,4,5,8-tetrahydroxyanthraquinone with an aliphatic amine compound in a dilute aqueous caustic alkali solution and in the presence of a metal catalyst.
U.S. Pat. No. 2,188,369, issued to McNally, provides for syntheses of substituted 1,4-diaminoanthraquinones wherein the 1-amino group is N-substituted with an alkylene sulfonic acid group.
U.S. Pat. Nos. 2,050,704, 2,185,709, and 2,191,029, issued to Koeberle, Ogilvie, and McNally, respectively, disclose methods of synthesizing N-substituted 1,4-diaminoanthraquinones from leuco-1,4-diaminoanthraquinone compounds as starting materials.
U.K. patent application Nos. 2,014,178 and 2,019,870 describe methods of preparing unsymmetrically substituted 1,4-diaminoanthraquinone compounds halogenated at either the 6- or 7-positions.
Known methods of synthesizing unsymmetrical aminoanthraquinones for the most part comprise multistep, lengthy reactions. Methods given in the literature for synthesizing such compounds have been tedious and complex.